Zoom lens system and camera incorporating the same

ABSTRACT

A zoom lens system, with a new structure that exhibits high optical performance over the entirety of a zoom range and the entirety of a focusing range, is disclosed. This zoom lens system comprises, in order from an object side to an image side: a front lens group which includes a plurality of lens units that move during zooming; a lens unit with negative optical power which moves during zooming and moves towards the object side during focusing from an infinity object to a close-distance object; and a lens unit with positive optical power which does not move for zooming.

This is a divisional of prior application Ser. No. 10/737,150, filedDec. 15, 2003, to which priority under 35 U.S.C. § 120 is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a zoom lens system that is favorable for asingle-lens reflex camera, digital still camera, video camera, filmcamera, etc., and exhibits good optical performance even while coveringa wide-angle range and being of large aperture diameter.

2. Description of the Related Art

As a prior-art image taking lens for a single-lens reflex camera, thereis known a zoom lens, in which lens units with negative, positive,negative, and positive refractive powers are disposed in that order froman object side to an image side (Japanese Laid-open Patent Application“1” to “6”).

Since this zoom type lens has a lens unit with negative refractive powerpositioned at the front and is a so-called negative lead type lens, itis suited for realizing a wider view angle at the wide-angle end.Meanwhile in regard to the telephoto end, since the first lens unit andthe second lens unit form a front component with positive refractivepower as a whole and the third lens unit and the fourth lens unit form arear component with negative refractive power as a whole, the opticalsystem can be arranged as a telephoto type lens system as a whole.

Meanwhile there is also known an optical system, wherein a lens unitwith positive refractive power is added to the zoom type lens,constituted of the abovementioned four lens units, to further improvethe optical performance (Japanese Laid-open Patent Application “7”).

There is also known an optical system in which a lens unit with negativerefractive power is added (Japanese Patent Publication “8”).

Also as focusing methods of a zoom lens, there are known the so-calledfront focus method, wherein the first lens unit at the most object sideis moved, and the so-called inner focus or rear focus method, whereinlens units from the second lens unit and rearwards are moved.

Generally with an inner focus or rear focus type zoom lens, since theeffective ray diameter of the first lens unit can be made small incomparison to a front focus type zoom lens, the advantage that theoverall lens system can be made compact is provided. Also, sincecomparatively compact and lightweight lens units are moved to performfocusing, the characteristic of facilitating rapid focusing, especiallyin autofocus cameras, which have become the mainstream recently, isprovided.

As such a zoom lens employing an inner focus or rear focus method, thepresent applicant has proposed in a so-called positive lead type zoomlens, having, in order from the object side to the image side, a firstlens unit with positive refractive power, a second lens unit withnegative refractive power, and a rear lens group with positiverefractive power as a whole, and with which zooming is performed byvarying the air spacing of the respective lens units, a zoom lenswherein a focusing lens unit with negative refractive power is disposedas a part of the rear lens group and this focusing lens unit is moved tothe image side to perform focusing from an infinity object to aclose-distance object (Japanese Laid-open Patent Application “9” to“12”).

[Japanese Laid-open Patent Application and Japanese Patent Publication]

-   “1”:Japanese Laid-open Patent Application No.H2(1990)-201310    (corresponding to U.S. Pat. No.5,000,550)-   “2”:Japanese Laid-open Patent Application No.H2(1990)-296208    (corresponding to U.S. Pat. No.5,000,550)-   “3”:Japanese Laid-open Patent Application No.H4(1992)-29109-   “4”:Japanese Laid-open Patent Application No.H4(1992)-29110-   “5”:Japanese Laid-open Patent Application No.H7(1995)-261084    (corresponding to U.S. Pat. No.5,710,669)-   “6”:Japanese Laid-open Patent Application No.H5(1993)-173071    (corresponding to U.S. Pat. No.5,276,553)-   “7”:Japanese Laid-open Patent Application No.H4(1992)-264412    (corresponding to U.S. Pat. No.5,229,886)-   “8”:Japanese Patent Publication No.2587218-   “9”:Japanese Laid-open Patent Application No.H3(1991)-225307    (corresponding to U.S. Pat. No.5,241,421)-   “10”:Japanese Laid-open Patent Application No.H3(1991)-225310    (corresponding to U.S. Pat. No.5,241,421)-   “11”:Japanese Laid-open Patent Application No.H4(1992)-186211    (corresponding to U.S. Pat. No.5,189,557)-   “12”:Japanese Laid-open Patent Application No.H4(1992) -186212    (corresponding to U.S. Pat. No.5,189,557)

A zoom lens, in which lens units with negative, positive, negative, andpositive refractive powers are disposed in that order from the objectside to the image side, and a zoom lens, which is an application of theabovementioned zoom lens and in which lens units with negative,positive, negative, and positive refractive powers as well as a rearlens group are disposed, are favorable as zoom lenses of wide viewangle. However, when an attempt is made to set the focal length and Fnumber at the telephoto side to desirable values and shorten the focallength at the wide-angle side while maintaining the optical performance,the overall lens system generally becomes large. This thus makes theprior-art zoom lenses unable to meet the demands made on zoom lenses forrecent optical equipment, which are being made significantly compact.

Meanwhile as another issue of wide-angle zoom lenses, it is difficult toperform focusing to a close-distance object while maintaining goodoptical performance.

For example, with the generally employed method of focusing from aninfinity object to a close-distance object by moving the first lens unitwith negative refractive power towards the object side, the front lensdiameter becomes large as the optical system is made wider in viewangle. Though various focusing methods have been proposed to resolvethis problem, all of these have the problem, though differing in degree,that the overall lens system becomes large.

For example, if the close-distance image taking distance is to be madeshort, the space for movement of the focusing lens unit had to be madelarge and this caused to the drive system to become large, the overalloptical system to become large, and the image performance forclose-distance image taking to degrade due to the aberration variationsaccompanying the focusing process.

Though an inner focus type arrangement has the abovementionedcharacteristics, when the realization of a wider view angle isattempted, the variations of the various aberrations that accompanyfocusing become significant and it becomes extremely difficult tomaintain good optical performance.

SUMMARY 0F THE INVENTION

An object of the present invention is to provide a zoom lens, with whicha wide view angle is realized and yet with which the various aberrationvariations that accompany zooming and focusing are reduced and highoptical performance is provided over the entire zooming range and theentire focusing range.

In order to achieve the above object, a zoom lens system of one aspectof the present invention comprises, in order from an object side to animage side, a front lens group which includes a plurality of lens unitsthat moves during zooming; a lens unit with negative optical power whichmoves during zooming and moves towards the image side during focusingfrom an infinity object to a close-distance object; and a lens unit withpositive optical power, which does not move for zooming.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a zoom lens system of Embodiment 1.

FIG. 2 is aberration diagrams of the zoom lens system of Embodiment 1when set at the wide-angle end and focused on an infinity object.

FIG. 3 is aberration diagrams of the zoom lens system of Embodiment 1when set at an intermediate zoom position and focused on an infinityobject.

FIG. 4 is aberration diagrams of the zoom lens system of Embodiment 1when set at the telephoto end and focused on an infinity object.

FIG. 5 is aberration diagrams of the zoom lens system of Embodiment 1when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 6 is aberration diagrams of the zoom lens system of Embodiment 1when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 7 is aberration diagrams of the zoom lens system of Embodiment 1when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 8 is a sectional view of a zoom lens system of Embodiment 2.

FIG. 9 is aberration diagrams of the zoom lens system of Embodiment 2when set at the wide-angle end and focused on an infinity object.

FIG. 10 is aberration diagrams of the zoom lens system of Embodiment 2when set at an intermediate zoom position and focused on an infinityobject.

FIG. 11 is aberration diagrams of the zoom lens system of Embodiment 2when set at the telephoto end and focused on an infinity object.

FIG. 12 is aberration diagrams of the zoom lens system of Embodiment 2when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 13 is aberration diagrams of the zoom lens system of Embodiment 2when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 14 is aberration diagrams of the zoom lens system of Embodiment 2when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 15 is a sectional view of a zoom lens system of Embodiment 3.

FIG. 16 is aberration diagrams of the zoom lens system of Embodiment 3when set at the wide-angle end and focused on an infinity object.

FIG. 17 is aberration diagrams of the zoom lens system of Embodiment 3when set at an intermediate zoom position and focused on an infinityobject.

FIG. 18 is aberration diagrams of the zoom lens system of Embodiment 3when set at the telephoto end and focused on an infinity object.

FIG. 19 is aberration diagrams of the zoom lens system of Embodiment 3when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 20 is aberration diagrams of the zoom lens system of Embodiment 3when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 21 is aberration diagrams of the zoom lens system of Embodiment 3when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 22 is a sectional view of a zoom lens system of Embodiment 4.

FIG. 23 is aberration diagrams of the zoom lens system of Embodiment 4when set at the wide-angle end and focused on an infinity object.

FIG. 24 is aberration diagrams of the zoom lens system of Embodiment 4when set at an intermediate zoom position and focused on an infinityobject.

FIG. 25 is aberration diagrams of the zoom lens system of Embodiment 4when set at the telephoto end and focused on an infinity object.

FIG. 26 is aberration diagrams of the zoom lens system of Embodiment 4when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 27 is aberration diagrams of the zoom lens system of Embodiment 4when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 28 is aberration diagrams of the zoom lens system of Embodiment 4when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 29 is a sectional view of a zoom lens system of Embodiment 5.

FIG. 30 is aberration diagrams of the zoom lens system of Embodiment 5when set at the wide-angle end and focused on an infinity object.

FIG. 31 is aberration diagrams of the zoom lens system of Embodiment 5when set at an intermediate zoom position and focused on an infinityobject.

FIG. 32 is aberration diagrams of the zoom lens system of Embodiment 5when set at the telephoto end and focused on an infinity object.

FIG. 33 is aberration diagrams of the zoom lens system of Embodiment 5when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 34 is aberration diagrams of the zoom lens system of Embodiment 5when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 35 is aberration diagrams of the zoom lens system of Embodiment 5when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 36 is sectional views of a zoom lens system of Embodiment 6.

FIG. 37 is aberration diagrams of the zoom lens system of Embodiment 6when set at the wide-angle end and focused on an infinity object.

FIG. 38 is aberration diagrams of the zoom lens system of Embodiment 6when set at an intermediate zoom position and focused on an infinityobject.

FIG. 39 is aberration diagrams of the zoom lens system of Embodiment 6when set at the telephoto end and focused on an infinity object.

FIG. 40 is aberration diagrams of the zoom lens system of Embodiment 6when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 41 is aberration diagrams of the zoom lens system of Embodiment 6when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 42 is aberration diagrams of the zoom lens system of Embodiment 6when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 43 is a sectional view of a zoom lens system of Embodiment 7.

FIG. 44 is aberration diagrams of the zoom lens system of Embodiment 7when set at the wide-angle end and focused on an infinity object.

FIG. 45 is aberration diagrams of the zoom lens system of Embodiment 7when set at an intermediate zoom position and focused on an infinityobject.

FIG. 46 is aberration diagrams of the zoom lens system of Embodiment 7when set at the telephoto end and focused on an infinity object.

FIG. 47 is aberration diagrams of the zoom lens system of Embodiment 7when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 48 is aberration diagrams of the zoom lens system of Embodiment 7when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 49 is aberration diagrams of the zoom lens system of Embodiment 7when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 50 is a sectional view of a zoom lens system of Embodiment 8.

FIG. 51 is aberration diagrams of the zoom lens system of Embodiment 8when set at the wide-angle end and focused on an infinity object.

FIG. 52 is aberration diagrams of the zoom lens system of Embodiment 8when set at an intermediate zoom position and focused on an infinityobject.

FIG. 53 is aberration diagrams of the zoom lens system of Embodiment 8when set at the telephoto end and focused on an infinity object.

FIG. 54 is aberration diagrams of the zoom lens system of Embodiment 8when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 55 is aberration diagrams of the zoom lens system of Embodiment 8when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 56 is aberration diagrams of the zoom lens system of Embodiment 8when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 57 is a sectional view of a zoom lens system of Embodiment 9.

FIG. 58 is aberration diagrams of the zoom lens system of Embodiment 9when set at the wide-angle end and focused on an infinity object.

FIG. 59 is aberration diagrams of the zoom lens system of Embodiment 9when set at an intermediate zoom position and focused on an infinityobject.

FIG. 60 is aberration diagrams of the zoom lens system of Embodiment 9when set at the telephoto end and focused on an infinity object.

FIG. 61 is aberration diagrams of the zoom lens system of Embodiment 9when set at the wide-angle end and focused on an object at 500 mm (fromthe image plane).

FIG. 62 is aberration diagrams of the zoom lens system of Embodiment 9when set at the intermediate zoom position and focused on an object at500 mm (from the image plane).

FIG. 63 is aberration diagrams of the zoom lens system of Embodiment 9when set at the telephoto end and focused on an object at 500 mm (fromthe image plane).

FIG. 64 is a schematic view of the principal parts of a single-lensreflex camera.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of a zoom lens system and a camera using the zoom lenssystem shall now be described using the drawings.

FIG. 1 is a sectional view of a zoom lens of Embodiment 1. FIG. 2, FIG.3, and FIG. 4 show aberration diagrams of the zoom lens of Embodiment 1when focused on an infinity object while being set at the wide-angleend, an intermediate zoom position, and the telephoto end, respectively.FIG. 5, FIG. 6, and FIG. 7 show aberration diagrams of the zoom lens ofEmbodiment 1 when focused on an object at a distance (distance from animage plane) of 500 mm while being set at the wide-angle end, theintermediate zoom position, and the telephoto end, respectively, withthe numerical values of numerical examples to be described below beingexpressed in units of mm.

FIG. 8 is a sectional view of a zoom lens of Embodiment 2. FIG. 9, FIG.10, and FIG. 11 show aberration diagrams of the zoom lens of Embodiment2 when focused on an infinity object while being set at the wide-angleend, an intermediate zoom position, and the telephoto end, respectively.FIG. 12, FIG. 13, and FIG. 14 show aberration diagrams of the zoom lensof Embodiment 2 when focused on an object at a distance (distance fromthe image plane) of 500 mm while being set at the wide-angle end, theintermediate zoom position, and the telephoto end, respectively, withthe numerical values of numerical examples to be described below beingexpressed in units of mm.

FIG. 15 is a sectional view of a zoom lens of Embodiment 3. FIG. 16,FIG. 17, and FIG. 18 show aberration diagrams of the zoom lens ofEmbodiment 3 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 19, FIG. 20, and FIG. 21 show aberration diagrams ofthe zoom lens of Embodiment 3 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 22 is a sectional view of a zoom lens of Embodiment 4. FIG. 23,FIG. 24, and FIG. 25 show aberration diagrams of the zoom lens ofEmbodiment 4 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 26, FIG. 27, and FIG. 28 show aberration diagrams ofthe zoom lens of Embodiment 4 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 29 is a sectional view of a zoom lens of Embodiment 5. FIG. 30,FIG. 31, and FIG. 32 show aberration diagrams of the zoom lens ofEmbodiment 5 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 33, FIG. 34, and FIG. 35 show aberration diagrams ofthe zoom lens of Embodiment 5 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 36 shows sectional views of a zoom lens of Embodiment 6, with (W)being the sectional view for the wide-angle end, (M) being that for anintermediate zoom position, and (T) being that for the telephoto end.FIG. 37, FIG. 38, and FIG. 39 show aberration diagrams of the zoom lensof Embodiment 6 when focused on an infinity object while being set atthe wide-angle end, an intermediate zoom position, and the telephotoend, respectively. FIG. 40, FIG. 41, and FIG. 42 show aberrationdiagrams of the zoom lens of Embodiment 6 when focused on an object at adistance (distance from the image plane) of 500 mm while being set atthe wide-angle end, the intermediate zoom position, and the telephotoend, respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 43 is a sectional view of a zoom lens of Embodiment 7. FIG. 44,FIG. 45, and FIG. 46 show aberration diagrams of the zoom lens ofEmbodiment 7 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 47, FIG. 48, and FIG. 49 show aberration diagrams ofthe zoom lens of Embodiment 7 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 50 is a sectional view of a zoom lens of Embodiment 8. FIG. 51,FIG. 52, and FIG. 53 show aberration diagrams of the zoom lens ofEmbodiment 8 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 54, FIG. 55, and FIG. 56 show aberration diagrams ofthe zoom lens of Embodiment 8 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

FIG. 57 is a sectional view of a zoom lens of Embodiment 9. FIG. 58,FIG. 59, and FIG. 60 show aberration diagrams of the zoom lens ofEmbodiment 9 when focused on an infinity object while being set at thewide-angle end, an intermediate zoom position, and the telephoto end,respectively. FIG. 61, FIG. 62, and FIG. 63 show aberration diagrams ofthe zoom lens of Embodiment 9 when focused on an object at a distance(distance from the image plane) of 500 mm while being set at thewide-angle end, the intermediate zoom position, and the telephoto end,respectively, with the numerical values of numerical examples to bedescribed below being expressed in units of mm.

Each of Embodiments 1 through 9 comprises, in order from an object side,a front lens group FL which includes a plurality of lens units thatmoves along an optical axis during zooming, a negative refractive powerlens unit BN that moves along the optical axis, and a positiverefractive power lens unit BP that is not moved for zooming, andfocusing from an infinity object to a close-distance object is performedby moving the abovementioned lens unit BN towards an image side.

The Embodiments 1 through 5, the sections of which are shown in FIG. 1,FIG. 8, FIG. 15, FIG. 22, and FIG. 29 shall be described first.

In each of FIG. 1, FIG. 8, FIG. 15, FIG. 22, and FIG. 29, L1 is a firstlens unit with negative refractive power (optical power=reciprocal ofthe focal length), L2 is a second lens unit with positive refractivepower, L3 is a third lens unit with negative refractive power, L4 is afourth lens unit with positive refractive power, L5 is a fifth lens unitwith negative refractive power, and L6 is a sixth lens unit withpositive refractive power. With each of the zoom lens systems of theEmbodiments 1 through 5, the front lens group FL is formed from thefirst to fourth lens units L1 to L4, the lens unit BN is constructedfrom the fifth lens unit L5, and the lens unit BP is constructed fromthe sixth lens unit L6.

SP is an aperture stop and SSP is an open F-number stop. IP is an imageplane at which a photosensitive plane of an image pickup means (asolid-state image pickup element (photoelectric conversion element)),such as a CCD sensor, CMOS sensor, etc., or a silver halide film) ispositioned. The aperture stop SP and the open F-number stop SSP moveintegrally with the third lens unit L3. The arrows in the figuresindicate the movement loci of the lens units in zooming from thewide-angle end to the telephoto end.

With each of Embodiments 1 through 5, the first to fifth lens units L1to L5 are moved so that in comparison to the wide-angle end, the spacingbetween the first lens unit L1 and the second lens unit L2 becomessmaller, the spacing between the second lens unit L2 and the third lensunit L3 becomes larger, the spacing between the third lens unit L3 andthe fourth lens unit L4 becomes smaller, the spacing between the fourthlens unit L4 and the fifth lens unit L5 becomes larger, and the spacingbetween the fifth lens unit L5 and the sixth lens unit L6 becomes largerat the telephoto end. The sixth lens unit L6 is fixed with respect tothe image plane IP.

Specifically, with each of the Embodiment 1, Embodiment 2, Embodiment 4,and Embodiment 5 of FIG. 1, FIG. 8, FIG. 22, and FIG. 29, in zoomingfrom the wide-angle end to the telephoto end, the first lens unit L1 ismoved towards the image side, the second lens unit L2 is moved towardsthe object side, the third lens unit L3 is moved along a part of a locusthat is convex towards the object side, the fourth lens unit L4 is movedintegrally with the second lens unit L2 towards the object side, and thefifth lens unit L5 is moved towards the object side.

With the Embodiment 3 of FIG. 15, the first lens unit L1 is movedtowards the image side, the second lens unit L2 is moved towards theobject side, the third lens unit L3 is moved towards the object side,the fourth lens unit L4 is moved integrally with the second lens unit L2towards the object side, and the fifth lens unit L5 is moved towards theobject side.

In each of Embodiments 1 through 5, the fifth lens unit L5 is movedtowards the image side to perform focusing from an infinity object to aclose-distance object. The wide-angle end and the telephoto end refer tozoom positions at which the lens units for zooming are positioned at therespective mechanical ends of the range in which the lens units aremovable along the optical axis.

With each of the zoom lenses of the Embodiments 1 through 5, at thewide-angle end, the first lens unit L1 with negative refractive powerbecomes a front component with negative refractive power, and the secondlens unit L2 and rearwards become a rear component with positiverefractive power, thus providing a retro-focus type power configurationthat is favorable for a wide angle lens.

Also at the telephoto end, the first lens unit L1 with negativerefractive power and the second lens unit L2 with positive refractivepower become a front component with positive refractive power as a wholeand the third lens unit L3 and rearwards become a rear component withnegative refractive power, thus providing a telephoto type powerconfiguration that is favorable for a telescopic lens. Good opticalperformance can thus be provided readily from the wide-angle end to thetelephoto end zoom positions and brightness (small F number) can besecured readily especially at the telephoto side.

Also by making the spacing between the fourth lens unit L4 and the fifthlens unit L5 become larger in zooming from the wide-angle end to thetelephoto end, the variation of an image plane that accompanies thezooming can be corrected more readily, and by making the spacing betweenthe fifth lens unit L5 and the sixth lens unit L6 become larger, thedistance from the optical axis to the off-axial rays that are madeincident on the sixth lens unit L6 is made greater to enable thepositive distortion that occurs at the second lens unit L2 to becorrected more readily.

Generally with a lens unit that makes up an optical system, in the casewhere the effective ray diameter is determined by the off-axial rays,the greater the angle (with the positive direction being thecounterclockwise direction from the optical axis) formed by the opticalaxis and the off-axial rays that are made incident onto the lens unit,the greater the variation of the effective ray diameter that occurs whenthe aperture and the distance change. With each of Embodiments 1 through5, since the off-axial rays that are made incident on the fifth lensunit L5 is refracted by the fourth lens unit L4 with positive refractivepower so that the angle formed by the optical axis and the off-axialrays will be small, the variation of the effective ray diameter thataccompanies the movement is small. Thus the fifth lens unit L5 is usedas a focusing lens unit and reduction of the lens diameter is achieved.

The fifth lens unit L5 for focusing comprises a positive lens and anegative lens. The aberration variations that occur during focusing arethereby made small. Also, the sixth lens unit L6, which is unmoved forzooming, comprises a single positive lens.

By making the second lens unit L2 move towards the object side inzooming from the wide-angle end to the telephoto end, the realization ofa telephoto type power configuration at the telephoto end isfacilitated, the setting of an appropriate telephoto ratio at thetelephoto end is facilitated, and the correction of the sphericalaberration and the curvature of field at the telephoto end isfacilitated in particular. Also by making the fourth lens unit L4 movetowards the object side, the positioning of the fifth lens unit L5 andthe sixth lens unit L6 at positions away from the image plane at thetelephoto end is facilitated and consequently, the securing of backfocal distance at the telephoto end is facilitated.

The second lens unit L2 and the fourth lens unit L4 are moved integrallyin zooming, thereby enabling simplification of the lens barrelstructure.

By moving the fifth lens unit L5 towards the object side in zooming fromthe wide-angle end to the telephoto end, the positioning of the sixthlens unit L6 at a position away from the image plane at the telephotoend is facilitated and consequently, the securing of back focal distanceat the telephoto end is facilitated.

With each of Embodiments 1 through 5:

-   -   The second lens unit L2 preferably comprises at least one        negative lens and at least one positive lens. The correction of        axial chromatic aberration at the telephoto end is thereby        facilitated.

The sixth lens unit L6 preferably has an aspherical surface of a shapewith which a positive refractive power increases from the optical axistowards the lens periphery. The correction of positive distortion at thetelephoto end is thereby facilitated.

The fifth lens unit L5 preferably comprises at least one negative lensand at least one positive lens. The variation of the chromaticaberration of magnification that accompanies zooming can thereby berestrained readily.

With each of Embodiments 1 through 5, in a case where a lens surface isto be made an aspherical surface, an aspherical surface layer of resin,etc. may be formed on the surface of a spherical lens as long as theaspherical surface is positioned at a part besides the surface at themost object side and the surface at the most image side of the lenssystem.

With each of Embodiments 1 through 5, when β5t is the lateralmagnification at the telephoto end of the fifth lens unit L5, βrt is thelateral magnification at the telephoto end of the lens unit positionedto the image side of the fifth lens unit L5, fi is the focal length ofthe abovementioned i-th lens unit, fw is the focal length of the overalloptical system at the wide-angle end, and ft is the focal length of theoverall optical system at the telephoto end, one or more the followingConditional Expressions is or are satisfied.1.1<|(1−β5t ²)×βrt ²|  (1)0.2<|f5/√{square root over ((fw×ft)}|<4.0  (2)0.5<f6/√{square root over (fw×ft)}<10.0  (3)0.8<|f1/fw|<2.3  (4)0.1<f2/ft<2.0  (5)0.5<|f3/fw|<4.5  (6)0.3<f4/ft<2.0  (7)0.2<|f5/ft|<1.9  (8)1.0<f6/fw<8.0  (9)

Each of Embodiments 1 through 5 do not have to satisfy all of theConditional Expressions (1) to (9) at the same time necessarily and maysatisfy one or more of the Conditional Expressions and each effect thatis in accordance with the satisfied Conditional Expression is therebyobtained.

The technical significance of the abovementioned Conditional Expressions(1) through (9) shall now be described.

The Conditional Expression (1) is for making the fifth lens unit L5favorable as a focusing lens unit. By satisfying this ConditionalExpression (1), an adequate focus sensitivity (focal point movementamount per movement amount of the focusing lens unit) can be secured forthe fifth lens unit L5 at the telephoto end, thus enabling the focusingmovement amount of the fifth lens unit L5 to be made small and therebyenabling the entire optical system to be made compact.

The Conditional Expression (2) is for setting the focal length of thefifth lens unit L5 appropriately.

By setting within the upper limit of the Conditional Expression (2), thecanceling out of the negative distortion that occurs at the first lensunit L1 with negative refractive power at the wide-angle end isfacilitated in particular, and by setting within the lower limit of theConditional Expression (2), the distance from the optical axis of theoff-axial rays that are made incident on the sixth lens unit L6 at thetelephoto end can be made small, thereby enabling the effective lensdiameter of the sixth lens unit L6 to be made small appropriately.

The Conditional Expression (3) is for setting the focal length of thesixth lens unit L6 appropriately.

By setting within the upper limit of the Conditional Expression (3), thesecuring of back focal distance at the wide-angle end is facilitated inparticular and by setting within the lower limit of the ConditionalExpression (3), the negative distortion at the wide-angle end can becorrected well readily.

The Conditional Expression (4) is for setting the focal length of thefirst lens unit L1 with negative refractive power appropriately. Bysatisfying the Conditional Expression (4), the correction of thenegative distortion at the wide-angle end and the making of the frontdiameter small can be achieved readily at the same time.

The Conditional Expression (5) is for setting the focal length of thesecond lens unit L2 with positive refractive power appropriately. Bysatisfying the Conditional Expression (5), the correction of thespherical aberration and the securing of a bright F number at thetelephoto end can be achieved readily at the same time.

The Conditional Expression (6) is for setting the focal length of thethird lens unit L3 with negative refractive power appropriately. Bysatisfying the Conditional Expression (6), the securing of a bright Fnumber at the telephoto end and the correction of the coma aberrationand distortion of the entire focal length range can be achieved readilyat the same time.

The Conditional Expression (7) is for setting the focal length of thefourth lens unit L4 with positive refractive power appropriately. Bysatisfying the Conditional Expression (7), the securing of the zoomratio and the correction of the negative distortion at the wide-angleend can be achieved readily at the same time.

The Conditional Expression (8) is for setting the focal length of thefifth lens unit L5 with negative refractive power appropriately. Bysatisfying the Conditional Expression (8), the variation of distortionthat accompanies zooming can be restrained readily.

The Conditional Expression (9) is for setting the focal length of thesixth lens unit L6 with positive refractive power appropriately. Bysatisfying the Conditional Expression (9), the securing of back focaldistance at the wide-angle end and the making of the rear diameter smallcan be achieved readily at the same time.

With each of Embodiments 1 through 5, in order to maintain even betteroptical performance, the numerical ranges of the Conditional Expression(1) through (9) are preferably set as follows:1.3<|(1−β5t ²)×βrt ²|  (1a)0.5<|f5/√{square root over ((fw×ft)}|<3.0  (2a)1.0<f6/√{square root over (fw×ft)}<4.0  (3a)1.0<|f1/fw|<2.0  (4a)0.3<f2/ft<1.3  (5a)1.5<|f3/fw|<3.5  (6a)0.4<f4/ft<1.4  (7a)0.4<|f5/ft|<1.7  (8a)2.0<f6/fw<6.0  (9a)

As has been described above, with each of Embodiments 1 through 5, awide-angle zoom lens, which covers a wide-angle region, has a zoom ratioof 2 times or more, has a large aperture of an F number of approximately2.8, and yet exhibits good optical performance, is realized.

Embodiments 6 through 9 of FIG. 36, FIG. 43, FIG. 50, and FIG. 57 shallnow be described.

In each of the lens sections of Embodiments 6 through 9 shown in FIG.36, FIG. 43, FIG. 50, and FIG. 57, L1 is a first lens unit with positiverefractive power, L2 is a second lens unit with negative refractivepower, and BR is a rear lens group with positive refractive power.

SP is an aperture stop and IP is an image plane at which aphotosensitive plane of an image pickup means (a solid-state imagepickup element or a silver halide film) is positioned. Rear lens groupBR comprises, in order from an object side, one or more lens units BRX(third to fifth lens units), a lens unit BRa (sixth lens unit) withnegative refractive power, and a lens unit BRb (seventh lens unit) withpositive refractive power.

The lens units BRX comprises, in order from the object side, a lens unitBR1 (third lens unit) with positive refractive power, a lens unit BR2(fourth lens unit) with negative refractive power, and a lens unit BR3(fifth lens unit) with positive refractive power. The arrows in thefigures indicate the movement loci of the lens units in zooming from thewide-angle end to the telephoto end. The first lens unit L1, the secondlens unit L2, and the lens units BR1 to BR3 constitute a front lensgroup.

With Embodiments 6 through 9, zooming is performed by moving the lensunits so that in comparison to the wide-angle end, the spacing betweenthe first lens unit L1 and the second lens unit L2 becomes larger andthe spacing between the second lens unit L2 and the rear lens group BRbecomes smaller at the telephoto end.

More specifically, in zooming from the wide-angle end to the telephotoend, the first lens unit L1 is moved towards the object side, the secondlens unit L2 is moved towards an image side, the lens unit BR1 (thirdlens unit) is moved towards the object side so that the spacing withrespect to the second lens unit L2 becomes larger, the lens unit BR2(fourth lens unit) is moved towards the object side so that spacing withrespect to the lens unit BR1 (third lens unit) becomes smaller, the lensunit BR3 (fifth lens unit) is moved integrally with the lens unit BR1(third lens unit) towards the object side so that the spacing withrespect to the lens unit BR2 (fourth lens unit) becomes smaller, and thelens unit BRa (sixth lens unit) is moved towards the object side whilechanging in the spacing with respect to the lens unit BR3 (fifth lensunit).

For zooming, the lens unit BRb (seventh lens unit) is fixed with respectto the image plane IP. The aperture stop SP moves integrally with thelens unit BR1 during zooming. Also, focusing from an infinity object toa close-distance object is performed by moving the lens unit BRa towardsthe image side.

Generally when a lens unit with positive refractive power is positionedat the image side of an optical system, the position of the image-sideprincipal point of the optical system moves towards the image side,thereby facilitating the securing of back focal distance. Oppositely,when a lens unit with negative refractive power is positioned at theimage side of an optical system, the position of the image-sideprincipal point of the optical system moves towards the object side andthe back focal distance tends to be short.

With the focal distancing lens unit BRa in each of the zoom lenses ofEmbodiments 6 through 9, even though the negative refractive power ofthe focusing lens unit is strengthened to make the focusing movementamount small, by positioning the lens unit BRb with positive refractivepower at the image side, the securing of back focal distance isfacilitated and an advantage is provided in realizing a wider view angleat the wide-angle end.

In particular, the focusing lens unit BRa comprises a negative lens, apositive lens, and a negative lens. The aberration variations that occurduring focusing are thus lessened. Also, the lens unit BRb, which isunmoved for zooming, comprises a single positive lens.

Furthermore with each of Embodiments 6 through 9, in zooming from thewide-angle side to the telephoto side, the spacing between the lens unitRBa and the lens unit RBb is made larger to facilitate the securing ofmovement space for the focusing lens unit even at the telephoto side atwhich the amount of movement of the image plane in accompaniment withthe variation of the object distance is large.

In particular, by moving the lens unit BRa to the object side in zoomingfrom the wide-angle end to the telephoto end, the positioning of thelens unit BRb at a position away from the image plane at the telephotoend is facilitated and consequently, the securing of back focal distanceat the telephoto end is facilitated.

Also, an aspherical surface is preferably used in order to maintain highoptical performance. As an aspherical surface to be used here, anaspherical surface layer of resin, etc. may be formed on the surface ofa spherical lens as long as the aspherical surface is positioned at apart besides the surface at the most object side and the surface at themost image side of the lens system.

With each of Embodiments 6 through 9, when βBRat is the lateralmagnification at the telephoto end of the lens unit BRa, βBRbt is thelateral magnification at the telephoto end of the lens unit BRb, fBRa isthe focal length of the lens unit BRa, fBRb is the focal length of thelens unit BRb, fw is the focal length of the overall optical system atthe wide-angle end, ft is the focal length of the overall optical systemat the telephoto end, fi is the focal length of the abovementioned i-thlens unit, fBRi is the focal length of the lens unit BRi, the lens unitBRa has at least one positive lens, and νp is the Abbe's number of thematerial of the positive lens inside the lens unit BRa (the averagevalue in a case where there are a plurality of positive lenses), one ormore the following Conditional Expressions is or are satisfied.3.0<|(1−βBRat ²)×βBRbt ²|  (10)0.1<|fBRa/√{square root over ((fw×ft))}|<0.9  (11)1.0<fBRb/√{square root over ((fw×ft))}<10.0  (12)νp<45  (13)1.0<f1/√{square root over ((fw×ft))}<3.0  (14)0.1<|f2|/√{square root over ((fw×ft))}<0.5  (15)0.2<fBR1/√{square root over ((fw×ft))}<0.8  (16)0.3<|fBR2/√{square root over ((fw×ft))}<1.0  (17)0.2<fBR3/√{square root over ((fw×ft))}<1.0  (18)

Each of Embodiments 6 through 9 do not have to satisfy all of theConditional Expressions (10) to (18) at the same time necessarily andmay satisfy one or more of the Conditional Expressions, and each effectthat is in accordance with the satisfied Conditional Expression isthereby obtained.

The technical significance of the abovementioned Conditional Expressions(10) through (18) shall now be described.

The Conditional Expression (10) is for making the lens unit BRafavorable as a focusing lens unit. By satisfying this ConditionalExpression (10), an adequate focus sensitivity (focal point movementamount per movement amount of the focusing lens unit) can be secured forthe lens unit BRa at the telephoto end, thus enabling the focusingmovement amount of the lens unit BRa to be made small and therebyenabling the entire optical system to be made compact.

The Conditional Expression (11) is for setting the focal length of thelens unit BRa appropriately.

By setting within the upper limit of the Conditional Expression (11),the canceling out of the negative distortion that occurs at the secondlens unit L2 with negative refractive power at the wide-angle end isfacilitated in particular, and by setting within the lower limit of theConditional Expression (11), the distance from the optical axis of theoff-axial rays that are made incident on the lens unit BRb at thetelephoto end can be made small, thereby enabling the effective lensdiameter of the lens unit BRb to be set appropriately.

The Conditional Expression (12) is for setting the focal length of thelens unit BRb.

By setting within the upper limit of the Conditional Expression (12),the securing of back focal distance at the wide-angle end is facilitatedin particular and by setting within the lower limit of the ConditionalExpression (12), the negative distortion at the wide-angle end can becorrected readily.

When the Conditional Expression (13) is satisfied, the variation of thechromatic aberration of magnification that accompanies zooming can berestrained more readily.

The Conditional Expression (14) is for setting the focal length of thefirst lens unit L1. When the upper limit of the Conditional Expression(14) is exceeded, an adequate telephoto type lens system cannot berealized at the telephoto side and the securing of a bright F numberbecomes difficult. Below the lower limit of the Conditional Expression(14), the front lens diameter will then to be large and unfavorable.

The Conditional Expression (15) is for setting the focal length of thesecond lens unit L2. Below the lower limit of the Conditional Expression(15), the correction of the negative distortion becomes difficultespecially at the wide-angle side, and when the upper limit of theConditional Expression (15) is exceeded, the securing of an adequatezoom ratio becomes difficult.

The Conditional Expression (16) is for setting the focal length of thelens unit BR1 appropriately. By satisfying the Conditional Expression(16), the aberrations that occur at the lens unit BR1 can be correctedreadily in a well-balanced manner by the other lens units and a highzoom ratio can be realized readily.

The Conditional Expression (17) is for setting the focal length of thelens unit BR2 appropriately. By satisfying the Conditional Expression(17), the securing of the zoom ratio and the correction of the flarethat is occurred by upper rays of the off-axial rays in the intermediatezoom region are facilitated further.

The Conditional Expression (18) is for setting the focal length of thelens unit BR3 appropriately. By satisfying the Conditional Expression(18), the securing of the zoom ratio and the correction of the negativedistortion at the wide-angle end can be achieved readily at the sametime.

With each of Embodiments 6 through 9, in order to maintain even betteroptical performance, the numerical ranges of the Conditional Expressions(10) through (18) are preferably set as follows:5.0<|(1−βBRat ²)×βBRbt ²|  (10a)0.25<|fBRa/√{square root over ((fw×ft))}|<0.7  (11a)2.0<fBRb/√{square root over ((fw×ft))}<7.0  (12a)νp<40  (13a)1.15<f1/√{square root over (fw×ft)}<2.5  (14a)0.15<|f2|/√{square root over ((fw×ft))}<0.3  (15a)0.3<fBR1/√{square root over ((fw×ft))}<0.6  (16a)0.4<|fBR2|/√{square root over ((fw×ft))}<0.75  (17a)0.3<fBR3/√{square root over ((fw×ft))}<0.6  (18a)

As has been described above, with Embodiments 6 through 9, a focusingsystem and a zoom lens employing the same, which cover a wide-angleregion, have a zoom ratio of approximately 10 times, and enable theshortening of the close-distance image taking distance withoutdegradation of good optical performance, can be realized readily.

An embodiment of a single-lens reflex camera that employs a zoom lensaccording to one of Embodiments 1 to 9 shall now be described withreference to FIG. 64. In FIG. 64, Reference numeral 10 shows a mainsingle-lens reflex camera body, 11 shows an interchangeable lensincorporating a zoom lens according to one of Embodiments 1 to 9.Reference numeral 12 shows a photosensitive plane of a silver halidefilm, a solid-state image pickup element (photoelectric conversionelement), or the like for recording an object image obtained through theinterchangeable lens 11. Reference numeral 13 shows a viewfinder opticalsystem for observing the object image from the interchangeable lens 11,and 14 shows a quick-return mirror that rotates to transmit the objectimage from the interchangeable lens 11 interchangingly to thephotosensitive plane 12 and the viewfinder optical system 13. Forobservation of the object image via the viewfinder, the object imagethat is formed on a focus plate 15 via the quick-return mirror 14 ismade an erect image by a pentaprism 16 and thereafter observed uponmagnification by an ocular optical system 17. For image taking, thequick-return mirror 14 is rotated in the direction of the arrow and theobject image is formed on the photosensitive plane 12 and recorded.

By thus applying the zoom lens according to Embodiments to an opticalapparatus, such as an interchangeable lens for single-lens reflexcamera, an optical apparatus of high optical performance can berealized.

The present invention can also be applied to a single-lens reflex camerawithout a quick-return mirror.

Numerical Examples 1 to 9, corresponding to Embodiment 1 to Embodiment9, respectively, of the present invention shall now be described. WithNumerical Examples, i indicates the order of a surface from the objectside, Ri indicates the radius of curvature of each surface, Di indicatesthe thickness or air spacing between the i-th and (i+1)-th opticalmembers, and Ni and vi are the refractive index and Abbe's number ford-line, respectively, of the i-th optical member.

Also, with R being the radius of curvature of the central part of asurface, X being the displacement in the optical axis direction(traveling direction of light) at a position of height Y from theoptical axis and with the surface apex being the reference point, and A,B, C, D, E, and F being aspherical coefficients, each aspherical surfaceis expressed by:

$X = {\frac{\left( {1/R} \right)Y^{2}}{1 + \sqrt{1 - \left( {Y/R} \right)^{2}}} + {AY}^{2} + {BY}^{4} + {CY}^{6} + {DY}^{8} + {EY}^{10} + {FY}^{12}}$

[e−x] expresses [×10^(−x)]. Also, the relationships between a part ofthe respective Conditional Expressions given above and the variousnumerical values of Numerical Examples are shown Tables 1 and 2.

Numerical example 1 f = 24.70~67.98 Fno = 2.92~3.25 2ω = 82.4~35.3 ‡ R1= 161.044 D1 = 2.50 N1 = 1.772499 ν1 = 49.5  R2 = 34.883 D2 = 12.15  R3= −164.700 D3 = 2.30 N2 = 1.772499 ν2 = 49.6  R4 = 67.311 D4 = 0.15  R5= 63.340 D5 = 5.04 N3 = 1.805181 ν3 = 25.4  R6 = 182.601 D6 = Variable R7 = 685.874 D7 = 1.90 N4 = 1.805181 ν4 = 25.4  R8 = 51.916 D8 = 6.23N5 = 1.772499 ν5 = 49.6  R9 = −127.867 D9 = 0.15  R10 = 91.053 D10 =3.83 N6 = 1.834807 ν6 = 42.7  R11 = −656.456 D11 = 0.15  R12 = 44.736D12 = 4.99 N7 = 1.696797 ν7 = 55.5  R13 = 580.418 D13 = Variable  R14 =Stop D14 = 2.21  R15 = −127.874 D15 = 1.30 N8 = 1.882997 ν8 = 40.8  R16= 44.148 D16 = 2.56  R17 = −104.764 D17 = 1.30 N9 = 1.719995 ν9 = 50.2 R18 = 33.858 D18 = 4.94 N10 = 1.805181 ν10 = 25.4  R19 = −110.923 D19 =0.69  R20 = Stop D20 = Variable  R21 = 122.859 D21 = 1.30 N11 = 1.846660ν11 = 23.9  R22 = 26.169 D22 = 6.42 N12 = 1.496999 ν12 = 81.5  R23 =−52.096 D23 = 0.15  R24 = 34.003 D24 = 4.55 N13 = 1.651597 ν13 = 58.5 R25 = −138.004 D25 = Variable  R26 = 326.115 D26 = 3.09 N14 = 1.846660ν14 = 23.9  R27 = −47.848 D27 = 0.15  R28 = −51.140 D28 = 1.20 N15 =1.834000 ν15 = 37.2  R29 = 26.555 D29 = Variable  R30 = 63.856 D30 =7.59 N16 = 1.583126 ν16 = 59.4 ‡ R31 = −98.162 Variable Focal lengthspacing 24.70 35.00 67.98 D6  55.58 31.43 3.13 D13 2.90 6.40 19.82 D2018.67 15.17 1.74 D25 1.19 3.49 10.67 D29 4.82 10.93 15.06 Asphericcoefficient Surface 1: A = 0.0000e+00 B = 1.19663e−10 C = 4.70286e=10 D= 1.28360e−12 E = 1.21542e−15 F = 4.19913e−19 Surface 31: A =−0.0000e+00 B = −1.86742e−07 C = −9.96565e−09 D = 6.00710e−11 E =−1.90097e−13  F = 2.27739e−16

Numerical example 2 f = 22.70~58.38 Fno = 2.90~3.26 2ω = 87.3~40.7 ‡ R1= 123.605 D1 = 2.50 N1 = 1.772499 ν1 = 49.6  R2 = 29.825 D2 = 13.13  R3= −106.694 D3 = 2.30 N2 = 1.772499 ν2 = 49.5  R4 = 82.370 D4 = 3.00  R5= 92.868 D5 = 4.00 N3 = 1.805181 ν3 = 25.4  R6 = 437.552 D6 = Variable R7 = 410.770 D7 = 1.90 N4 = 1.805181 ν4 = 25.4  R8 = 52.875 D8 = 6.03N5 = 1.717004 ν5 = 47.9  R9 = −119.460 D9 = 0.15  R10 = 86.807 D10 =3.57 N6 = 1.834807 ν6 = 42.7  R11 = −647.303 D11 = 0.15  R12 = 47.266D12 = 4.51 N7 = 1.696797 ν7 = 55.5  R13 = 505.161 D13 = Variable  R14 =Stop D14 = 2.13  R15 = −151.295 D15 = 1.30 N8 = 1.882997 ν8 = 40.8  R16= 49.052 D16 = 1.95  R17 = −303.974 D17 = 2.72 N9 = 1.799516 ν9 = 42.2 R18 = 37.202 D18 = 3.91 N10 = 1.846660 ν10 = 23.9  R19 = −187.667 D19 =0.98  R20 = Stop D20 = Variable  R21 = 126.439 D21 = 1.30 N11 = 1.846660ν11 = 23.9  R22 = 26.548 D22 = 6.83 N12 = 1.496999 ν12 = 81.5  R23 =−51.005 D23 = 0.15  R24 = 32.556 D24 = 4.69 N13 = 1.617722 ν13 = 49.8 R25 = −132.456 D25 = Variable  R26 = −204.803 D26 = 2.68 N14 = 1.846660ν14 = 23.9  R27 = −41.551 D27 = 0.15  R28 = −46.661 D28 = 1.20 N15 =1.834000 ν15 = 37.2  R29 = 28.810 D29 = Variable  R30 = 67.617 D30 =8.05 N16 = 1.583126 ν16 = 59.4 ‡ R31 = −68.737 Variable Focal lengthspacing 22.70 35.00 58.38 D6  49.50 21.29 1.50 D13 2.88 8.24 20.31 D2019.19 13.83 1.77 D25 1.19 4.99 11.75 D29 4.00 10.46 13.67 Asphericcoefficent Surface 1: A = 0.00000e+00 B = 2.04437e−06 C = 6.895383−10 D= 2.46407e−18 E = 70925e−15 F = −1.00883e−18 Surface 31: A =−0.00000e+00 B = 1.97079e−06 C = −1.94774e−10 D = 1.27725e−10 E =−3.19694e−13 F = 3.51352e−16

Numerical example 3 f = 20.60~48.58 Fno = 2.90~3.35 2ω= 92.8~48.0 ‡ R1 =134.542 D1 = 2.50 N1 = 1.772499 ν1 = 49.6  R2 = 27.188 D2 = 13.78  R3 =−78.185 D3 = 2.30 N2 = 1.834807 ν2 = 42.7  R4 = 97.239 D4 = 3.00  R5 =229.018 D5 = 4.62 N3 = 1.805181 ν3 = 25.4  R6 = −119.495 D6 = Variable R7 = 274.749 D7 = 2.80 N4 = 1.516330 ν4 = 64.1  R8 = −122.916 D8 = 0.15 R9 = 108.113 D9 = 1.90 N5 = 1.751821 ν5 = 26.5  R10 = 37.302 D10 = 6.06N6 = 1.517417 ν6 = 62.4  R11 = −153.717 D11 = 0.15  R12 = 37.916 D12 =4.28 N7 = 1.834807 ν7 = 42.7  R13 = 827.789 D13 = Variable  R14 = StopD14 = 2.15  R15 = −150.776 D15 = 1.30 N8 = 1.882997 ν8 = 40.8  R16 =56.320 D16 = 2.96  R17 = −249.978 D17 = 1.25 N9 = 1.834807 ν9 = 42.7 R18 = 28.355 D18 = 5.54 N10 = 1.805181 ν10 = 25.4  R19 = −111.253 D19 =0.70  R20 = Stop D20 = Variable  R21 = 298.278 D21 = 1.30 N11 = 1.846660ν11 = 23.9  R22 = 25.523 D22 = 6.76 N12 = 1.496999 ν12 = 81.5  R23 =−53.374 D23 = 0.15  R24 = 36.174 D24 = 4.63 N13 = 1.712995 ν13 = 53.9 R25 = −106.296 D25 = Variable  R26 = −70.596 D26 = 1.84 N14 = 1.846660ν14 = 23.9  R27 = −46.779 D27 = 0.15  R28 = −87.418 D28 = 1.20 N15 =1.834807 ν15 = 42.7  R29 = 29.748 D29 = Variable  R30 = 56.914 D30 =8.04 N16 = 1.583126 ν16 = 59.4 ‡ R31 = −79.720 Variable Focal lengthspacing 20.60 27.94 48.58 D6  51.99 28.30 1.50 D13 2.74 4.33 12.95 D2012.34 10.75 2.13 D25 1.19 4.88 12.68 D29 3.15 8.17 12.97 Asphericcoefficent Surface 1: A = 00000e+00 B = 3.71994e−08 C = 1.14775e−09 D =−2.5363e−13 E = 1.29688e−15 F = −6.25550e−19 Surface 31: A =−0.00000e+00 B = 3.33792e−06 C = −2.38616e−08 D = 1.41155e−10 E =3.97666e−13 F = 4.30136e−16

Numerical example 4 f = 17.50~38.64 Fno = 2.90~3.47 2ω = 102.1~58.5 ‡ R1= 170.715 D1 = 2.50 N1 = 1.772499 ν1 = 49.6  R2 = 20.601 D2 = 14.51  R3= −53.500 D3 = 2.30 N2 = 1.804000 ν2 = 46.6  R4 = 607.412 D4 = 1.67  R5= 81.370 D5 = 2.82 N3 = 1.805181 ν3 = 25.4 ‡ R6 = 526.843 D6 = Variable R7 = 96.443 D7 = 4.17 N4 = 1.582673 ν4 = 46.4  R8 = −567.926 D8 = 0.15 R9 = 55.537 D9 = 1.90 N5 = 1.761821 ν5 = 26.5  R10 = 20.113 D10 = 7.34N6 = 1.517417 ν6 = 52.4  R11 = −128.843 D11 = 0.15  R12 = 49.324 D12 =4.18 N7 = 1.651597 ν7 = 58.5  R13 = −284.150 D13 = Variable  R14 = StopD14 = 2.34  R15 = −88.745 D15 = 1.30 N8 = 1.882997 ν8 = 40.8  R16 =69.569 D16 = 1.13  R17 = −2084.655 D17 = 1.25 N9 = 1.882997 ν9 = 40.8 R18 = 23.480 D18 = 8.64 N10 = 1.805181 ν10 = 25.4  R19 = −155.701 D19 =0.95  R20 = Stop D20 = Variable  R21 = 141.268 D21 = 1.30 N11 = 1.846660ν11 = 23.9  R22 = 29.443 D22 = 6.93 N12 = 1.495999 ν12 = 81.5  R23 =−58.983 D23 = 0.15  R24 = 39.554 D24 = 6.32 N13 = 1.589130 ν13 = 61.1 R25 = −85.186 D25 = Variable  R26 = −73.538 D26 = 1.85 N14 = 1.846660ν14 = 23.9  R27 = −56.343 D27 = 0.15  R28 = 214.109 D28 = 1.20 N15 =1.834807 ν15 = 42.7 ‡ R29 = 32.563 D29 = Variable  R30 = 46.730 D30 =7.13 N16 = 1.487490 ν16 = 70.2  R31 = −196.608 Variable Focal lengthspacing 17.50 24.00 38.64 D6  35.21 19.54 5.00 D13 2.21 5.64 17.21 D2016.94 13.51 1.94 D25 1.18 5.61 14.79 D29 2.27 8.77 9.63 Asphericcoefficient Surface 1: A = 0.00000e+00 B = 1.05853e−06 C = 4.31049e−09 D= 5.72891e−12 E = 1.84562e−17 F = 7.13953e−19 surface 6: A = 0.00000e+00B = 3.13215e−06 C = 2.14047e−09 D = 1.36230e−11 E = 4.18879e−14 F =3.14497e−17 Surface 29: A = 0.00000e+00 B = 3.14396e−06 C = 1.97029e−08D = 1.89008e−10 E = 7.33403e−13 F = 1.08139e−15

Numerical example 5 f = 15.45~33.98 Fno = 2.90~3.33 2ω = 108.9~65.0 ‡ R1= 92.533 D1 = 2.50 N1 = 1.772499 ν1 = 49.6  R2 = 23.411 D2 = 21.77  R3 =−95.356 D3 = 2.30 N2 = 1.804000 ν2 = 46.6  R4 = 93.439 D4 = 3.00  R5 =69.502 D5 = 3.73 N3 = 1.846660 ν3 = 23.9 ‡ R6 = 160.973 D6 = Variable R7 = −397.286 D7 = 3.20 N4 = 1.617722 ν4 = 49.8  R8 = −198.878 D8 =0.15  R9 = 62.345 D9 = 1.90 N5 = 1.761821 ν5 = 26.5  R10 = 30.395 D10 =6.94 N6 = 1.517417 ν6 = 52.4  R11 = −83.804 D11 = 0.15  R12 = 43.966 D12= 4.05 N7 = 1.677900 ν7 = 55.3  R13 = −216.458 D13 = Variable  R14 =Stop D14 = 2.21  R15 = 164.995 D15 = 1.30 N8 = 1.882997 ν8 = 40.8  R16 =88.797 D16 = 3.36  R17 = −72.757 D17 = 1.25 N9 = 1.882997 ν9 = 40.8  R18= 22.478 D18 = 8.60 N10 = 1.805181 ν10 = 25.4  R19 = −96.860 D19 = 2.30 R20 = Stop D20 = Variable  R21 = 120.586 D21 = 1.30 N11 = 1.846660 ν11= 23.9  R22 = 31.305 D22 = 7.43 N12 = 1.496999 ν12 = 81.5  R23 = −42.078D23 = 0.15  R24 = 38.952 D24 = 5.95 N13 = 1.516330 ν13 = 64.1 ‡ R25 =−110.475 D25 = Variable  R26 = −59.043 D26 = 1.44 N14 = 1.846660 ν14 =23.9  R27 = −55.437 D27 = 0.15  R28 = 238.252 D28 = 1.20 N15 = 1.834807ν15 = 42.7 ‡ R29 = 30.403 D29 = Variable  R30 = 36.986 D30 = 4.95 N16 =1.583126 ν16 = 59.4 ‡ R31 = 552.279 Variable Focal length spacing 15.4520.00 33.98 D6  50.29 25.99 5.03 D13 2.30 1.80 12.99 D20 15.01 15.504.32 D25 1.50 7.83 13.86 D29 1.50 2.81 4.52 Aspheric coefficient Surface1: A = 0.00000e+00 B = 4.67142e−06 C = 1.41100e−09 D = 8.75148e−13 E =1.60628e−16 F = 2.51806e−20 Surface 6: A = 0.00000e+00 B = 1.49406e−06 C= −6.31444e+09 D = 2.34297e−11 E = −4.91178e−14 F = 3.59501e−17 Surface25: A = 0.00000e+00 B = −7.73118e−07 C = 7.26783e−11 D = −2.27820e−11 E= 8.09270e−14 F = −9.97880e−17 Surface 29: A = 0.00000e+00 B =−1.24689e−06 C = −4.32541e−09 D = 3.51094e−11 E = −2.59044e−14 F =−1.50164e−16 Surface 31: A = −0.00000e+00 B = 5.84931e−06 C =−3.10476e−08 D = 3.51094e−10 E = −9.53206e−13 F = 1.33118e−15

Numerical example 6 f = 28.80~339.99 Fno = 3.59~5.66 2ω = 73.8~7.3  R1 =119.245 D1 = 3.00 N1 = 1.834000 ν1 = 37.2  R2 = 69.427 D2 = 8.31 N2 =1.496999 ν2 = 81.6  R3 = 2874.028 D3 = 0.16  R4 = 81.906 D4 = 6.94 N3 =1.496999 ν3 = 81.6  R5 = 1880.891 D5 = Variable  R6 = 197.630 D6 = 1.90N4 = 1.772499 ν4 = 49.6  R7 = 22.885 D7 = 6.75  R8 = −142.776 D8 = 1.50N5 = 1.834807 ν5 = 42.7  R9 = 48.996 D9 = 0.15  R10 = 36.010 D10 = 4.52N6 = 1.698947 ν6 = 30.1  R11 = −364.028 D11 = 2.34  R12 = −38.722 D12 =1.40 N7 = 1.834807 ν7 = 42.7  R13 = 63.605 D13 = 3.40 N8 = 1.846660 ν8 =23.9  R14 = −115.913 D14 = Variable  R15 = Stop D15 = 1.40  R16 =151.712 D16 = 1.50 N9 = 1.805181 ν9 = 25.4  R17 = 49.354 D17 = 4.73 N10= 1.487490 ν10 = 79.2  R18 = −58.993 D18 = 0.15  R19 = 86.284 D19 = 2.99N11 = 1.487490 ν11 = 79.2  R20 = −132.595 D20 = 0.15  R21 = 46.167 D21 =3.35 N12 = 1.572501 ν12 = 57.7  R22 = −923.062 D22 = Variable  R23 =−145.199 D23 = 1.50 N13 = 1.651597 ν13 = 58.5  R24 = 143.348 D24 = 1.71 R25 = −68.339 D25 = 1.50 N14 = 1.622992 ν14 = 58.2  R26 = 36.247 D26 =3.50 N15 = 1.805181 ν15 = 25.4  R27 = 147.323 D27 = Variable  R28 =381.611 D28 = 1.50 N16 = 1.846660 ν16 = 23.9  R29 = 35.008 D29 = 6.33N17 = 1.487490 ν17 = 79.2  R30 = −42.191 D30 = 0.15  R31 = 122.413 D31 =3.25 N18 = 1.517417 ν18 = 52.4  R32 = −104.441 D32 = 0.15  R33 = 38.319D33 = 6.60 N19 = 1.496999 ν19 = 81.5  R34 = −45.455 D34 = 1.50 N20 =1.806098 ν20 = 41.0  R35 = −109.278 D35 = Variable  R36 = 116.121 D36 =1.50 N21 = 1.834807 ν21 = 42.7  R37 = 20.308 D37 = 0.54  R38 = 21.236D38 = 9.37 N22 = 1.620041 ν22 = 36.3  R39 = −29.161 D39 = 0.16  R40 =−31.343 D40 = 1.80 N23 = 1.712995 ν23 = 53.9  R41 = 31.521 D41 =Variable ‡ R42 = 201.994 D42 = 4.00 N24 = 1.487490 ν24 = 79.2  R43 =−248.556 Variable Focal length spacing 28.80 100.00 339.99 D5  1.8038.63 78.19 D14 43.28 15.09 1.00 D22 1.90 11.43 15.13 D27 16.72 6.192.50 D35 1.10 3.99 2.00 D41 6.06 31.50 39.41 Aspheric coefficientSurface 42: A = 0.00000e+00 B = 2.66098e−06 C = 5.15592−09 D =−1.18901e−17 E = 0.00000+00 F = 0.00000e+00

Numerical example 7 f = 28.80~291.99 Fno = 3.45~5.65 2ω = 73.8~8.5 R1 =98.551 D1 = 3.00 N1 = 1.834000 ν1 = 37.2 R2 = 59.470 D2 = 8.70 N2 =1.496999 ν2 = 81.6 R3 = 1004.462 D3 = 0.15 R4 = 68.082 D4 = 6.31 N3 =1.496999 ν3 = 81.6 R5 = 830.984 D5 = Variable R6 = 282.673 D6 = 1.90 N4= 1.772499 ν4 = 49.6 R7 = 21.675 D7 = 6.52 R8 = −153.161 D8 = 1.60 N5 =1.834807 ν5 = 42.7 R9 = 53.032 D9 = 0.15 R10 = 35.150 D10 = 3.49 N6 =1.698947 ν6 = 30.1 R11 = 134.601 D11 = 3.08 R12 = −37.255 D12 = 1.40 N7= 1.834807 ν7 = 42.7 R13 = 119.074 D13 = 3.40 N8 = 1.846660 ν8 = 23.9R14 = −62.450 D14 = Variable R15 = Stop D15 = 1.40 R16 = 133.785 D16 =1.50 N9 = 1.805181 ν9 = 25.4 R17 = 54.930 D17 = 4.41 N10 = 1.487490 ν10= 79.2 R18 = −58.595 D18 = 0.15 R19 = 77.676 D19 = 2.84 N11 = 1.487490ν11 = 79.2 R20 = −177.325 D20 = 0.15 R21 = 44.747 D21 = 2.94 N12 =1.572501 ν12 = 57.7 R22 = 304.019 D22 = Variable R23 = −123.489 D23 =1.50 N13 = 1.651597 ν13 = 58.5 R24 = 183.723 D24 = 1.46 R25 = −78.748D25 = 1.50 N14 = 1.622992 ν14 = 58.2 R26 = 30.113 D26 = 3.60 N15 =1.805181 ν15 = 25.4 R27 = 113.618 D27 = Variable R28 = 446.193 D28 =1.50 N16 = 1.846660 ν16 = 23.9 R29 = 35.578 D29 = 6.64 N17 = 1.487490ν17 = 79.2 R30 = −39.083 D30 = 0.15 R31 = 171.593 D31 = 3.26 N18 =1.517417 ν18 = 52.4 R32 = −89.047 D32 = 0.15 R33 = 36.619 D33 = 6.41 N19= 1.496999 ν19 = 81.5 R34 = −61.736 D34 = 1.50 N20 = 1.806098 ν20 = 41.0R35 = −142.697 D35 = Variable R36 = 234.444 D36 = 1.50 N21 = 1.834807ν21 = 42.7 R37 = 23.318 D37 = 0.48 R38 = 24.136 D38 = 9.74 N22 =1.620041 ν22 = 36.3 R39 = −29.954 D39 = 0.15 R40 = −31.189 D40 = 1.80N23 = 1.712995 ν23 = 53.9 R41 = 42.831 D41 = Variable R42 = −60.465 D42= 4.00 N24 = 1.487490 ν24 = 79.2 R43 = −39.054 Variable Focal lengthspacing 28.80 100.00 291.99 D5  1.80 28.59 62.92 D14 39.69 9.69 1.00 D222.34 13.21 16.29 D27 16.95 6.08 3.00 D35 1.99 7.40 2.03 D41 8.18 34.5243.72

Numerical example 8 f = 24.70~291.95 Fno = 3.21~5.66 2ω = 82.4~8.5  R1 =311.656 D1 = 8.00 N1 = 1.834009 ν1 = 37.2  R2 = 92.339 D2 = 10.34 N2 =1.496999 ν2 = 81.6  R3 = −374.337 D3 = 0.15  R4 = 89.364 D4 = 7.95 N3 =1.651597 ν3 = 58.6  R5 = 777.330 D5 = Variable ‡ R6 = 490.643 D6 = 1.90N4 = 1.772499 ν4 = 49.6  R7 = 20.909 D7 = 6.30  R8 = −133.118 D8 = 1.60N5 = 1.834807 ν5 = 42.7  R9 = 73.437 D9 = 0.15  R10 = 36.131 D10 = 3.69N6 = 1.693947 ν6 = 30.1  R11 = 246.684 D11 = 1.88  R12 = −62.097 D12 =1.40 N7 = 1.824807 ν7 = 42.7  R13 = 50.441 D13 = 3.40 N8 = 1.844660 ν8 =23.9  R14 = −274.434 D14 = Variable  R15 = stop D15 = 1.40  R16 = 31.940D16 = 1.50 N9 = 1.805181 ν9 = 25.4  R17 = 32.005 D17 = 4.52 N10 =1.487490 ν10 = 79.2  R18 = −67.414 D18 = 0.15  R19 = 103.688 D19 = 2.70N11 = 1.487490 ν11 = 79.2  R20 = −106.172 D20 = 0.15  R21 = 45.087 D21 =2.96 N12 = 1.572601 ν12 = 57.7  R22 = −242787.481 D22 = Variable  R23 =−104.599 D23 = 1.50 N13 = 1.651597 ν13 = 58.5  R24 = 127.364 D24 = 1.78 R25 = −53.678 D25 = 1.60 N14 = 1.622992 ν14 = 58.2  R26 = 26.147 D26 =3.60 N15 = 1.805181 ν15 = 25.4  R27 = 116.134 D27 = Variable  R28 =151.298 D28 = 1.50 N16 = 1.846660 ν16 = 23.9  R29 = 32.559 D29 = 6.70N17 = 1.487490 ν17 = 79.2  R30 = −46.548 D30 = 8.15  R31 = 205.161 D31 =3.36 N18 = 1.517417 ν18 = 52.4  R32 = −81.934 D32 = 0.15  R33 = 41.236D33 = 1.29 N19 = 1.496999 ν19 = 81.5  R34 = −33.538 D34 = 1.50 N20 =1.806098 ν19 = 81.5  R35 = −62.853 D35 = Variable  R36 = 656.920 D36 =1.50 N21 = 1.824807 ν20 = 41.0  R37 = 28.222 D37 = 0.60  R38 = 29.549D38 = 1.27 N22 = 1.620041 ν21 = 42.7  R39 = −35.906 D39 = 0.16  R40 =−51.361 D40 = 1.80 N23 = 1.712995 ν23 = 36.3 ‡ R41 = 40.999 D41 =Variable ‡ R42 = 39.548 D42 = 4.00 N24 = 1.487490 ν24 = 79.2  R43 =44.826 Variable Focal length spacing 24.70 100.00 291.95 D5  1.80 43.7491.52 D14 35.54 6.13 0.99 D22 2.08 15.31 17.30 D27 17.72 4.49 2.50 D351.97 8.85 1.99 D41 1.39 27.19 39.14 Aspheric coeffient Surface 6: A =0.00000e+00 B = 1.13766e−06 C = −6.21654e−10 D = −6.26234e−13 E =0.00000e+00 F = 0.00000e+00 Surface 41: A = 0.00000e+00 B = 4.50346e−06C = 1.06751e−08 D = −1.81550e−12 E = 0.00000e+00 F 0.00000e+00 Surface42: A = 0.00000e+00 B = 6.40151e−07 C = 4.63968e−06 D = −1.888842e−12 E= 0.00000e+00 F = 0.00000e+00

Numerical example 9 f = 24.70~232.95 Fno = 3.43~6.66 2ω = 82.4~10.6  R1= 274.104 D1 = 3.00 N1 = 1.834000 ν1 = 37.2  R2 = 92.370 D2 = 10.15 N2 =1.496999 ν2 = 31.6  R3 = −1506.814 D3 = 0.15  R4 = 91.730 D4 = 8.06 N3 =1.696797 ν3 = 55.5  R5 = 466.203 D5 = Variable ‡ R6 = 139.867 D6 = 1.90N4 = 1.772499 ν4 = 49.6  R7 = 18.885 D7 = 7.57  R8 = −126.323 D8 = 1.60N5 = 1.834807 ν5 = 42.7  R9 = 82.344 D9 = 0.15  R10 = 34.221 D10 = 3.47N6 = 1.698947 ν6 = 30.1  R11 = 116.347 D11 = 2.61  R12 = −49.558 D12 =1.40 N7 = 1.834807 ν7 = 42.7  R13 = 92.243 D13 = 3.40 N8 = 1.848860 ν8 =23.9  R14 = −97.348 D14 = Variable  R15 = Stop D15 = 1.40  R16 = 104.602D16 = 1.50 N9 = 1.805131 ν9 = 25.4  R17 = 40.960 D17 = 4.98 N10 =1.487490 ν10 = 79.2  R18 = −55.542 D18 = 0.16  R19 = 92.515 D19 = 2.73N11 = 1.487490 ν11 = 79.2  R20 = −156.976 D20 = 0.15  R21 = 47.122 D21 =3.69 N12 = 1.572501 ν12 = 57.7  R22 = −150.170 D22 = Variable  R23 =−24.011 D23 = 1.50 N13 = 1.551597 ν13 = 58.5  R24 = 94.241 D24 = 1.43 R25 = −159.388 D25 = 1.50 N14 = 1.622992 ν14 = 58.2  R26 = 25.292 D26 =3.60 N15 = 1.805181 ν15 = 28.4  R27 = 84.890 D27 = Variable  R28 =78.893 D28 = 1.50 N16 = 1.846660 ν16 = 23.9  R29 = 29.483 D29 = 5.69 N17= 1.487490 ν17 = 79.2  R30 = −62.333 D30 = 0.15  R31 = −693.362 D31 =2.35 N18 = 1.517417 ν18 = 52.4  R32 = −98.643 D32 = 0.15  R33 = 43.894D33 = 8.38 N19 = 1.496999 ν19 = 81.9  R34 = −27.135 D34 = 1.60 N20 =1.806098 ν20 = 41.0  R35 = −52.462 D35 = Variable  R36 = −373.303 D36 =1.50 N21 = 1.834807 ν21 = 42.7  R37 = 28.754 D37 = 1.29  R38 = 41.301D38 = 7.86 N22 = 1.620041 ν22 = 26.3  R39 = −27.599 D39 = 0.15  R40 =−37.547 D40 = 1.80 N23 = 1.712995 ν23 = 52.9 ‡ R41 = 67.177 D41 =Variable ‡ R42 = −748.920 D42 = 4.00 N24 = 1.487499 ν24 = 79.2  R43 =−93.833 Variable Focal length spacing 24.70 100.00 232.95 D5  1.80 62.6598.97 D14 40.15 11.63 1.30 D22 1.83 12.07 15.82 D27 16.48 6.24 2.49 D352.00 4.01 7.92 D41 3.59 31.71 34.99 Aspheric coefficient Surface 6: A =0.00000e+00 B = 1.71252e+06 C = −7.05369e−10 D = −8.10676e−13 E =0.00000e+00 F 32 0.00000e+00 Surface 41: A = 0.00000e+00 B = 4.02700e−06C = 1.76133e−08 D = −6.14451e−11 E = 0.00000e+00 F = 0.00000e+00 Surface42: A = 0.00000e+00 B = 1.66062e−06 C = 8.22956e−09 D = −7.23875e−12 E =0.00000e+00 F = 0.00000e+00

TABLE 1 Numerical Numerical Numerical Numerical Numerical Conditionalexpression example 1 example 2 example 3 example 4 example 5 1a 1.1 <|(1 − β5t²) × βrt²| 2.66 2.89 2.97 1.53 1.78 2a |f5/{square root over((fw × ft))}| 0.91 0.90 1.00 2.12 1.90 3a f6/{square root over ((fw ×ft))} 1.65 1.64 1.84 3.01 2.96 4a |f1/fw| 1.50 1.42 1.52 1.32 1.66 5af2/ft 0.48 0.57 0.69 0.86 1.00 6a |f3/fw| 1.76 2.19 2.71 2.78 2.99 7af4/ft 0.57 0.63 0.79 1.05 1.15 8a |f5/ft| 0.55 0.56 0.65 1.43 1.28 9af6/fw 2.73 2.63 2.83 4.47 4.38

TABLE 2 Conditional Numerical Numerical Numerical Numerical expressionexample 6 example 7 example 8 example 9 1b |(1 − βBRat²) × 8.37 7.606.15 6.02 βBRbt²| 2b |fBRa/{square root over ((fw × ft))}| 0.35 0.420.54 0.62 3b fBRb/{square root over ((fw × ft))} 2.32 2.32 6.50 2.90 4bυp < 45 36.26 36.26 36.26 36.26 5b f1/{square root over ((fw × ft))}1.31 1.22 1.71 2.25 6b |f2|/{square root over ((fw × ft))} 0.20 0.210.23 0.26 7b fBR1/{square root over ((fw × ft))} 0.35 0.39 0.39 0.41 8b|fBR2|/{square root over ((fw × ft))} 0.56 0.60 0.55 0.62 9bfBR3/{square root over ((fw × ft))} 0.37 0.39 0.40 0.41

1. A zoom lens system comprising, in order from an object side to animage side: a front lens group, which includes a plurality of lens unitsthat move during zooming; a lens unit with negative refractive power,which moves during zooming and moves towards the image side duringfocusing from an infinity object to a close-distance object; and a lensunit with positive refractive power which does not move for zooming. 2.The zoom lens system according to claim 1, wherein the zoom lens systemforms an image on a photoelectric conversion element.
 3. A cameracomprising: the zoom lens system according to claim 1; and aphotoelectric conversion element receiving an image formed by the zoomlens system.